Method of preparing ocif3

ABSTRACT

1. THE METHOD OF MAKING OCIF3 COMPRISING REACTING CINO3 WITH F2 AND RECOVERING OCIF3.

United States Patent T 3,692,476 METHOD OF PREPARING OCIF DonaldPilipovich, Canoga Park, and Carl J. Schack,

Chatsworth, Califi, assignors to North American Aviation, Inc.

No Drawing. Filed May 13, 1966, Ser. No. 551,490

Int. Cl. C01b 11/00, 11/02 U.S. Cl. 423-466 4 Claims This inventionrelates to a method of synthesizing oxychlorine trifluoride. Inco-pending application, Ser. No. 543,493, filed Apr. 13, 1966, having acommon assignee, oxychlorine trifluoride, OCIF was disclosed as a newoxidizer compound. Additionally, two methods of the compound are setforth. One of the methods relates to reacting Cl O with fluorine. Whilethe second method comprises reacting Cl O with an alkali metal fluorideto form a complex with subsequent fluorination of the complex to obtainOClF The object of the herein invention is to disclose additionalmethods of making the oxidizer OClF in higher yields.

Both of the methods of this invention involve reacting fluorine withchlorine nitrate to obtain OClF The first method of this inventioninvolves complexing chlorine nitrate with an alkali metal fluoridepowder. The second method involves reacting fluorine and chlorinenitrate in the absence of a complexing agent.

FIRST METHOD In the first method, fluorine is then added and thereaction transpires, proceeding at a low temperature, under 20 C., toproduce oxychlorine trifluoride according to the following reactions:

I ClONO: +MF -r MF-ClONO III A M'ClFiO MF ClFsO In the above reactions Mis an alkali metal.

More specifically, the first method involves condensing the reactantsinto a suitable reactor which can be of a material such as stainlesssteel. The reactor is first loaded, for example, with cesium fluoride,CsF, a white hydroscopic powder. The loading takes place in an inertatmosphere chamber. Chlorine nitrate is then admitted to the reactor andallowed to complex with the CsF at a low temperature. There is noshaking or stirring or such required. Fluorine is then added to thereactor and the reaction proceeds to produce OCIF Using the cesiumfluoride as a complexing agent, the reaction has yielded over a 95percent conversion of ClNO to OClF In addition to CsF, other alkalimetal fluorides, such as NaF, KF, and RbF can be successfully used ascomplexing agents with the chlorine nitrate.

SECOND METHOD The same general reaction involving the fluorination ofchlorine nitrate can transpire successfully in the absence of alkalimetal fluoride powder. The reaction is carried out by reacting thefluorine with chlorine nitrate. After standing for a suitable period atlower than ambient temperatures, the products which are all volatile maybe vacuum fractionated. Therefore, no pyrolysis is needed to obtain ClFO. This second method without the utilization of the alkali metalfluoride can yield in excess of 84 percent conversion of ClNO to OC'IF3,692,476 Patented Sept. 19, 1972 The reaction temperature of thefiuorination of chlorine nitrate in accord with the two methods shouldbe maintained below room temperature in a static system using a closedreactor. In the second method of the invention when a complexing agentis not used, the reaction can be of a flow type rather than a closedreactor. In this case the ClNO and F can be brought together in a hottube. The time of the reaction can proceed from shortly after the timethat it begins to several days. The ultimate completion of the reactioncan be determined by observing the decrease of pressure in the reactor.In carrying out both methods an excess of fluorine over thatstoichiometrically required is preferred to ensure complete conversionof the chlorine nitrate. Likewise, when the complexing agent is used, anexcess thereof is preferred.

Upon completion of the reactions of both materials, the closed reactor,when such is used, can then be connected to a series of traps maintainedat different temperatures. For example, a trap can be convenientlymaintained at 196 C., the temperature of liquid nitrogen. In this trapall of the products would remain except fluorine. This, thus, becomesthe method for removing from the completed reaction the excess fluorine,if any is present. The nitryl fluoride, FNO will pass a trap at 78 C.,yet the trap will retain the basic product OC'lF The 78 C. is again aconvenient temperature since this is the temperature of Dry Ice. Thus,after removing both the eX- cess fluorine and the nitryl fluoride, theremainin contents are warmed to ambient temperature. The non-volatilespresent when CsF powder is used which can include Cs+ClF O are pyrolyzedat temperatures up to 250 C. Following are specific examples of themethod of making OClF according to the invention:

EXAMPLE I A 5.5 gram sample of CsF was loaded into a milliliterstainless steel cylinder which was situated in a dry box so that nomoisture would contact the CsF. Following, 75 cc. of ClNO was condensedinto the cylinder at 196 C. The cylinder was then closed and kept at 18C. for two days to form the CsF complex of CINOa. At this point, 2liters of F were condensed into the cylinder at 196 C. After six days at78 C. the excess F was pumped out of the cylinder or bomb at 196 C.,while the remaining room temperature volatiles were fractionated,yielding a large amount of FNO and about 25 cc. of OClF in thefractionation. The solids remaining in the reactor were then pyrolyzedfor 30 minutes with pumping at approximately 200 C. In this manner, anadditional 50 cc. of OClF was obtained. Overall the reaction yieldedgreater than percent conversion of ClNO to OClF EXAMPLE II In thisexample ClNO was reacted with F in the absence of the cesium fluoridepowder. An 87 cc. sample of ClNO and approximately 3 liters of F werecondensed into a ml. stainless steel bomb at -196 C. After six weeks at78 C. the F was pumped off at 196 C. and the remaining material vacuumfractionated. In addition to FNO a small amount of ClF was found. Thesetwo materials were then fractionated oil. The desired product, OClF wasobtained in a 73.5 cc. quantity. This represents an 84 percent yieldbased on the amount of ClNO utilized.

Although the invention has been described and illustrated in detail, itis to be clearly understood that the same is by way of illustration andexample only and is not to be taken by way of limitation, the spirit andscope of this invention being limited only by the terms of the appendedclaims.

We claim:

1. The method of making OClF comprising reacting CINO with P andrecovering OC1F 2. The method of claim 1 wherein said reaction iscarried out at temperatures less than 20 C.

3. The method of claim 1 wherein said C1NO is first complexed with analkali metal fluoride prior to reaction with said F 4. The method ofclaim 3 wherein said alkali metal fluoride is CsF.

4 References Cited LELAND A. SEBASTIAN, Primary Examiner US. Cl. X.R.423-472

1. THE METHOD OF MAKING OCIF3 COMPRISING REACTING CINO3 WITH F2 ANDRECOVERING OCIF3.